1. Field of the Invention
The present invention relates to an image interpolating device provided in a digital camera, for example, to improve color image quality.
2. Description of the Related Art
Conventionally, there is known a digital camera in which a color filter of the Bayer arrangement is provided on a light receiving surface of an imaging device such as a CCD so as to sense a color image. The color filter is formed by arranging red(R), green(G), and blue(B) color filter elements in a checkerboard arrangement, and the color filter elements correspond to photodiodes of the imaging device. Therefore, a pixel signal of a color, which corresponds to each of the color filter elements, is generated by each of the photodiodes. For example, an R pixel signal is generated by a photodiode corresponding to an R color filter element.
A pixel signal may be subjected to an interpolating process so that a color image having a higher quality is obtained, in comparison with the case in which a pixel signal output from the imaging device is used just as it is. In a usual interpolating process, regarding an objective pixel from which an R-signal is obtained by a photodiode, a G-signal is generated by taking an average of the G-signals of pixels positioned around the objective pixel, and a B-signal is generated by taking an average of the B-signals of pixels positioned around the objective pixel. However, for example, in an image in which spatial frequency is high, the actual color of the objective pixel, for which a color is to be obtained by interpolation, may be largely different from the actual colors of the pixels around the objective pixel. In such a case, chromatic blur occurs because of the color signal of the pixel obtained by interpolation.